Hi Mike,
I have a photocopy of some data that I believe came from VCC records, showing 1931 and 1932 models as all starting with "Y7". The last one on the page is 1932 Y7 5033, so presumably your one is 1933 or 1934, depending on how many they actually produced in those years ? Shame I haven't got the next page from their records - probably has numbers listed close to what you have.
For info, it also shows the 1931 & 1932 engine numbers with "Y10" prefix and numbers ranging from 570 up to 2535.
Cheers,
Bevan